The present disclosure relates to a smart entry system and method for a vehicle, and particularly relates to a smart entry system and method that provides a dynamic search area corresponding to a selected smart entry function.
Smart entry systems are currently used by many vehicle manufacturers. Heretofore, however, smart entry has been routinely applied to four-door sedans, and sometimes two-door coupes, but rarely to sport utility vehicles and the like, particularly those employing a powered tailgate.
Smart entry systems only require that a user have a key fob to access the vehicle if it is locked. The user need not perform any physical operation on the key fob (e.g., pushing of a button), but can leave the fob in a pocket, purse, etc. In operation, the vehicle will detect the presence of the fob based on sensors and/or switches. When triggered, the vehicle will send a low frequency (LF) search field. Within the search field, the vehicle looks for or searches for the key fob (e.g., sends out a request signal). If found, the key fob will reply to the request signal or search field via RF communications. For example, the key fob will send back a unique identifier confirming that it is properly associated with the vehicle.
A problem can occur when existing smart entry systems are employed in conjunction with certain vehicle closures, such as powered tailgates, for example. In particular, it is common to limit the range of the search field for minimizing any security risks associated with the smart entry system. However, in the example of a powered tailgate, the operator typically must move back relative to a rear edge of the vehicle for closing the tailgate and/or operating a close/lock switch or actuator. Moving back can undesirably remove the operator and the fob carried by the operator from the search field. This results in competing considerations: if power is constant and low, security will be enhanced, but the system will not have enough range to reach the fob when the powered tailgate is open; in contrast, if power is constant and high, security will not be as good, but the range will be suitable for finding the key fob.